Hi,
Molybdenum Disulfide is an additive added to grease, it is attracted to the metal surface and protects the bearing surface even if most of the grease has gone.
The ALKO 1300 was a standard fit on the Eriba Touring (pop-top) caravans until recently, and a lot of Eriba owners change the pads themselves. From 2005 Eribas are fitted with either the ALKO 2004 or Winterhoff.
The pads should last for 25,000 miles, but most Eriba owners change the pads more often because of contamination - and the squeaks.
All you need to do is remove two ring-clips, and the pads slide out - but take care with the replacements clips because they are single shot. And they are dead easy to lose - a big sheet of newspaper under the coupling will save a lot of cursing.
On the ALKO 1300 you need to apply a smear of Moly Disulfide grease on the pins on the back of the pads, and a further smear on the bearing surface inside the coupling. A small tube (15 ml) from Halfords will do the job and leave you plenty for another future replacement.
Robert